Rollup merge of #140431 - bend-n:dont_handle_bool_transmute, r=Nadrieril

dont handle bool transmute

removes `transmute(u8) -> bool` suggestion due to ambiguity, leave it for clippy

elaboration on ambiguity in question:
`transmute::<u8, bool>(x)` will codegen to an `assume(u8 < 2)`;
`_ == 1` or `_ != 0` or `_ % 2 == 0` would remove that assumption
`match _ { x @ (0 | 1) => x == 1, _ => std::hint::unreachable_unchecked() }` is very verbose

`@rustbot` label L-unnecessary_transmutes

Author: matthiaskrgr